Brake Issues
I don't like dot 5 fluid...it seems to give a "soft" or spongy pedal. I'd verify that the pads were installed correctly. The "pins" on top are different for inside and outside pads. The inside pad has the longer (taller?) vertical pin on the top, the outboard pad has the shorter one. You can get them backwards and it will bind the caliper. I'm not sure it would cause your problem, but it is worth checking.
1. caliper is not moving freely on the caliper guide pins
2. if your car has TCS and you invoke it alot it will cause more wear to the rear pads(long shot)
3. pads are contaminated or wrong pad compound


